Re: MTU to CDN's

[Jared Mauch <jared () puck nether net>]

Bah, never mind.. reading my PCAP wrong :-(


> On Jan 19, 2018, at 8:58 AM, Jared Mauch <jared () puck nether net> wrote:
>
>
>
> > On Jan 18, 2018, at 8:44 PM, William Herrin <bill () herrin us> wrote:
> >
> > > Which packet?  Is there a specific CDN that does this?  I’d be curious to see
> > > data vs speculation.
> >
> > Howdy,
> >
> > Path MTU discovery (which sets the DF bit on TCP packets) is enabled
> > by default on -every- operating system that's shipped for decades now.
> > If you don't want it, you have to explicitly disable it. Disabling it
> > for any significant quantity of traffic is considered antisocial since
> > routers generally can't fragment in the hardware fast path.
>
> I’m not seeing this in a PCAP capture to at least one CDN, either from my
> host or from the CDN endpoint.
>
> I suspect you’re mistaken.
>
> - Jared
>
> PCAP: https://puck.nether.net/~jared/akamai.pcap